A steel sheet used for fuel tanks of an automobile, a motorcycle, and so on is required to have corrosion resistance to fuel such as gasoline on a surface thereof. A Sn—Pb based plated steel sheet has been broadly used as the steel sheet for fuel tanks. In recent years, due to a restriction on Pb, a plated steel sheet as an alternative to the Sn—Pb based plated steel sheet has been developed (Patent Literatures 1 to 4).
A Zn—Ni based plated steel sheet, which is one alternative material to the Sn—Pb based plated steel sheet, has the advantage of exhibiting good corrosion resistance to gasoline at low cost, and in recent years, the use of the Zn—Ni based plated steel sheet in emerging countries has been increasing.
However, fuel tanks manufactured by using the Zn—Ni based plated steel sheet sometimes cannot obtain sufficient corrosion resistance to fuel. The corrosion resistance to a fuel containing alcohol in particular is liable to be insufficient, and thus a hole is sometimes formed for a short period of time.
A corrosion-resistant member for biofuel containing alcohol is described in Patent Literature 5. However, even when a fuel tank is manufactured by using the materials described in Patent Literature 5 to a reproducible extent, sufficient corrosion resistance cannot be obtained.